The present invention relates to an illuminator for a microscope. More particularly, the present invention relates to a support for an illuminator which permits the projection of a beam of light from the illuminator along an axis generally coaxial with a line of vision through a microscope.
When using a microscope for magnification of a subject, it is often necessary to illuminate the subject to be viewed with a beam of light. The need for illumination is particularly true for physicians that require a microscope for magnifying a subject during surgery or medical examinations. For example, certain types of eye surgery require a microscope and an illuminator. In eye surgery for removal of cateracts or implantation of a lens, an illuminator for the microscope is necessary in order to properly illuminate the eye.
In such medical situations, the microscope is usually mounted on a stand having a cantilevered arm for supporting the microscope over the subject to be viewed. Thus, the illuminator for such a cantilever-supported microscope must provide sufficient light without interfering with the line of vision through the microscope. Further, the illuminator should be positioned to provide sufficient illumination without interfering with the physician's arms and hands, i.e., without interfering with the physician's manual dexterity.
A conventional support for a microscope and illuminator is illustrated in FIGS. 1A and 1B. The support includes a base 10 having a size sufficient to ensure its stability in all directions. A post 12 extends from the base and adjustably supports a boom arm 14 through a bracket 16. The bracket 16 preferably permits vertical adjustment of the height of the boom arm 14 on the post 12. In addition, the bracket 16 permits lateral adjustment of the boom arm 14 relative to the bracket 16, i.e., extension of the boom arm 14 by varying the longitudinal position of the bracket on the boom arm. If necessary, the bracket 16 may permit angular adjustment of the boom arm 14 relative to the post 12.
The boom arm 14 has a microscope holder 20 on one end and a counterweight 18 on an opposite end. The microscope holder 20 is removably secured to the end of the boom arm 14 by clamps 22 which permit variations of the position of the microscope holder on the boom arm. For example, the clamp 22 may permit adjustment of the angular position of the microscope relative to the boom arm.
The microscope holder 20 has an opening 24 therethrough surrounded by a microscope supporting face 26. The size of the opening 24 is sufficient to receive a microscope 28 (FIG. 1B) having an eyepiece 30 and a lens 32. The lens 32 is inserted through the opening 24 so that a face 34 of the microscope rests on the supporting face 26 of the microscope holder 20. The microscope 28 may be fixed to the microscope holder 20 by any suitable fastening device. Thus, the physician may place the subject (e.g., the eye of the patient) beneath the lens 32 of the microscope and view the subject through the eyepiece 30. A line of vision A is defined through the lens 32. The microscope holder may be provided with adjustment knobs 38 for focusing the microscope on the subject.
In order to illuminate the subject, the microscope holder 20 includes a light holder 40 for supporting an illuminator 42. Preferably, the illuminator 42 is a 20 watt Quartz Hallogen light tube having a light source in a large block 44 and a tube 46 extending from the block 44. A beam of light B is projected through the tube 46 toward the subject beneath the lens 32. Such light tubes are well known and will not be described in detail.
To support the illuminator 42, the tube 46 is inserted into an angled bore 48 (illustrated in phantom in FIGS. 1A and 1B) of the light holder 40 on the microscope holder 20, the bore being located to one side of the opening 24 for the microscope. The bore 48 has a diameter and length sufficient to receive and support the tube 46 at a position adjacent to the lens 32 of the microscope. The angle of the bore 48 supports the tube 46 so that the beam of light B is projected onto the subject at an angle a of approximately 15.degree. from the line of vision A.
The above-described microscope and illuminator support are satisfactory in most circumstances. However, since the illuminator projects light along a line B angled at approximately 15.degree. with respect to the line of vision A, the illuminator may not provide sufficient illumination of the subject to be viewed. This is particularly true for illuminating an eye during eye surgery for cataracts. If the cataract is not sufficiently illuminated, then portions of the cataract may not be seen by the physician and thus not removed. Another concern particularly noted by physicians is that the position of the illuminator may interfere with the physician's hands and/or cast shadows on the subject.
The present invention was created to obviate the above-noted disadvantageous features of known microscope holders. It is an object of the present invention to remedy these drawbacks by providing a support for an illuminator which permits light to be directed along a line generally coaxial with the line of vision for improving the illumination of the subject.
A further object of the present invention is to provide a support for an illuminator which projects a beam of light at an angle (e.g., 5.degree.-8.degree.) less than the angle associated with known illuminator supports (e.g. 15.degree.).
It is another object of the present invention to provide a support for an illuminator which does not cast shadows over the subject or interfere with a physician's manual dexterity.
These and other objects and advantages are obtained by the present invention which relates to a generally coaxial illuminator. In a preferred embodiment, the coaxial illuminator includes a plate having an aperture therethrough for reception of a lens of a microscope. A line of vision is defined by the axis of the lens. The plate includes bracket means for supporting an illuminator on one side of the microscope. The illuminator projects a beam of light on a subject beneath the lens. The bracket means supports the illuminator so that the beam of light is projected along a line generally coaxial with the line of vision. Preferably, the illuminator support in accordance with the invention permits the projection of a beam of light at an angle in the range of approximately 5.degree.-8.degree. from the line of vision.